<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="button" value="播放">
</body>
<script>
    var btn=document.querySelector('input');
    btn.onclick=function () {
        if(btn.value == '播放'){
            btn.value = '暂停';
        }else{
            btn.value = '播放'
        }
    }
</script>
</html>